Tape wrapping device with plural independently rotatable spool carriers

ABSTRACT

A device for winding tape around a continuous strand of material, for example a cable, wherein two reels of tape (11, 12) are mounted on a rotating tape feed device (1) via individual reel carriers (13, 14) which rotate independently and coaxially with the strand of material, so that each empty reel of tape can be stopped, exchanged, and brought back into operation while the tape feed device (1) is still rotating. The tape can therefore be placed around the strand of material without the device being stopped. In order to change the reel of tape, it is only necessary to reduce the rotational speed of the tape feed device (1).

BACKGROUND OF THE INVENTION

The invention relates to a device for placing at least one tape around acontinuous strand of material, particularly for putting tape around acable, the device being provided with a driven tape feeding device forthe tape which rotates about the longitudinal axis of the strand andincludes a tape reel.

Continuous strands of material, particularly cables, are encased in oneor two tapes of paper, plastic, metal and/or fabric made of fibers ormetal wires. In many cases, the thus wound or taped strand of materialis subsequently provided with an additional plastic sheath. Theapplication of the plastic sheath is effected by way of coextrusion,that is, the taped strand of material is conducted through anappropriately configured extruder. The tape length required for tapingis greater by a multiple than the length of the strand of material, sothat the device as a whole must be stopped each time and held at astandstill until the empty tape reel has been exchanged (for) a fulltape reel and the outgoing tape end has been connected with the incomingtape end. Since the extruder must be kept at its required temperatureduring the time of the standstill, the practice in the past has been tocontinuously draw plastic material through a discharge conduit duringthe period of standstill to thus prevent damage due to overheating tothe plastic in the extruder itself and to the already applied plasticsheath still in the region of the extruder nozzle. Aside from theconsiderable losses in plastic occurring during the standstill period,there also exists the danger that, due to the influence of greater heatduring the standstill period, the sheathing will be damaged.

SUMMARY OF THE INVENTION

It is the object of the invention to configure a device of theabove-identified type so that continuous operation and, at the sametime, an exchange of reels and the joining of the tape end and the tapebeginning is possible during operation.

This is accomplished according to the invention in that at least twotape reels are provided which are each supported on a reel carrier thatis mounted so as to rotate independently of the tape feeding device andcoaxially with the strand of material. Each reel carrier has anassociated releasable coupling so as to connect it with the tape feedingdevice in a manner secure against rotation and each reel carrier isprovided with a device to guide the leading tape end. In such a device,the tape feeding device is composed, for example, of a rotor whichrotates coaxially about the longitudinal axis of the strand and isprovided with guide and tensioning elements for the tape to be applied.The rate of advance of the strand of material and the rate of rotationof the rotor are here determined by the pitch of the wound tape.Depending on the intended use, several tapes, also tapes of differentmaterials, can be applied in one process step. In the device accordingto the invention, two tape reels are provided for each type of tape,with the tape always being fed from one tape reel and applied to thestrand of material, while the other tape reel rotates along. When thetrailing end of the tape reel in operation has left the reel, guidedevices now cause the leading end of the tape from the second tape reelto be fed in and to be connected with the trailing tape end so that thetaping process can be continued without stoppage. Depending on the typeof connection that is employed to connect the trailing tape end with theleading tape end, the rate of advance of the strand of material, on theone hand, and the rate of rotation of the tape feeding device, on theother hand, can here be reduced over a short period of time, so that areliable and proper connection can be effected between the outgoingtrailing tape end and the incoming leading tape end. As soon as this hashappened, the device is able to be brought back to its full operatingspeed. This has the advantage, particularly when taping strands ofmaterial, for example cables, which after the taping process areprovided with a thermoplastic material by way of coextrusion, that therewill be no stoppage in the region of the extruder but instead the strandof material continues to move, albeit at a reduced speed, through theextruder nozzle. By way of an appropriate control, the extrusion outputof the extruder can then be reduced, while nevertheless a sheathing ofuniform quality is applied to the strand of material. The discharge ofsurplus plastic as required when the extruder is stopped, is herecompletely unnecessary.

Another advantage of the invention is that the strand of materialcontinues to move even when tapes are changed so that a considerablygreater throughput is realized here compared to systems in which themachine must be stopped for a change of tapes. During or after bringingthe tape feeding device to its operational rate of rotation, thecoupling of the reel carrier holding the now empty tape reel is releasedand the reel carrier is stopped. The empty reel can now be exchanged fora full reel during operation. At the end of the exchange of reels, thereel carrier is coupled back to the rotating tape feeding device so thata full tape reel again rotates along as a reservoir reel.

As one expedient feature of the invention, the coupling is provided witha controllable start-up slip so that the associated reel carrier can bepositively accelerated from a standstill to the operating rate ofrotation by way of the driven tape feeding device. In this connection,it is particularly expedient for the coupling to be an electromagneticcoupling.

A further feature of the invention provides that each reel carrier isequipped with a brake to fix it relative to the machine frame. In thisway, it is ensured that the reel carrier remains fixed at a standstilland cannot be carried along by residual friction forces transmitted byway of the coupling.

As a further, preferred feature it is provided that the real carriersare each equipped with a position sensor which acts with respect to themachine frame and which is connected with a control device that acts onthe brake to cause the tape reel, upon application of the brake, to beput into a predetermined alignment relative to the machine frame whenthe real carrier is stopped. This configuration has the advantage thatthe reel carriers are always reliably stopped in the same orientationrelative to the machine frame when the reel carriers are at a standstillso that the exchange of tape reels can also be automatized. This isdone, for example, by way of corresponding supply magazines and grippingdevices which, after the release of a lock, lift the empty tape reelfrom the reel carrier and then place a full tape reel on it. Sincecustomarily the strand of material to be taped is guided horizontallythrough the machine, it is advisable to have the tape reel disposedabove the strand of material whenever the reel carrier is stopped. Thenit is possible to arrange transporting means for supplying full reelsand removing empty reels above the taping device and to provide one orseveral supply magazines for full tape reels.

An advantageous feature of the invention provides that each reel carrieris equipped with at least one counterweight for the tape reel. Themagnitude of the weight depends, on the one hand, on the gross weight ofa full reel, that is, also on the tape material employed in each case,and is advisably designed in such a manner that the centrifugal forcesgenerated by the counterweight and acting on the reel carrier holding afull reel, on the one hand, and those generated by the tape reel, on theother hand, are approximately compensated. If the mass of thecounterweight is designed to be somewhat smaller than the mass of a fulltape reel, the remaining imbalance with a full reel, on the one hand,and a completely or almost completely empty reel, on the other hand,still remains within permissible limits since after transfer of the tapeend from a full reel, the tape feeding device is accelerated from a lowrate of rotation to a high operating rate of rotation and quantities oftape are already being removed during this acceleration phase. As soonas the tape reel in operation has a predetermined amount of tape left,the rate of rotation of the tape feeding device is again reduced so thatthe imbalance now caused by the greater mass of the counterweight canagain be tolerated in view of the decreasing rate of rotation.

A preferred feature of the invention provides that a two-partcounterweight is disposed at each reel carrier and the two partialweights are preferably mounted so that during operation they can beadjusted relative to one another circumferentially in oppositedirections by means of an adjustment drive. This arrangement has theadvantage that, by appropriately displacing the partial weights relativeto one another, the counterweight can be set for any desired reelweight, thus making it possible to process different tape materialswithout it being necessary to exchange the counterweights or add orremove additional weights. A particular advantage of this arrangement isthat, if an appropriately configured adjustment drive is provided, thepartial weights can be adjusted relative to one another during operationcorresponding to the decrease in reel weight. In this way, the rotorformed by the reel carrier, the reel and the counterweight can always bekept in balance, and thus practically at the operating rate of rotationduring the entire "trip" of a tape reel. The start-up time from the slowrate of rotation to the operating rate of rotation once a tape reel isput into operation and the braking time to the low rate of rotationrequired during the time in which the trailing tape end is connected tothe leading tape end of the next tape reel can here also be reduced.Another particular advantage is that, when the two partial weights areadjusted by rotating them about the axis of rotation of the reelcarrier, even centrifugal forces do not cause the partial weights to bedisplaced so that the adjustment forces required for continuousadjustment need be only of such magnitude that the friction of thebearings for the partial weights and, in the acceleration phase, theaccelerating forces of the partial weights in the circumferentialdirection need be overcome. Since, however, in this embodiment the tapefeeding device can be brought up very quickly to a then constantoperating rate of rotation, it is possible to effect continuousadjustment without force until the system is braked shortly before theend of the tape since the partial weights are subjected to practicallyno mass acceleration in the circumferential direction.

As a further advantageous feature of the invention, it is provided thatthe tape feeding device is equipped with a tape supply arm and includesa positioning device which acts on the coupling by way of a controldevice so that, in the operating position, each tape reel is held in apredetermined orientation relative to the tape supply arm. Thepositioning device is here advisably configured so that the two reelsare oriented diametrally to one another. Thus, after the exchange of anempty tape reel for a full tape reel, the positioning device is able toact on the coupling control to position the reel carrier so as to causethe guiding device of the reel carrier holding the new, full tape reelto be positioned precisely on the tape supply arm so that, when a "tapeend" signal for the reel in operation is generated, the leading tape endcan be supplied to the tape supply arm to be connected with the outgoingtape end.

As a further feature of the invention, it is provided that each reelcarrier is equipped with a driven tape guide which drives the tapeand/or the reel at least when the leading end of the tape is threadedinto the tape supply arm. In this way it is possible to accelerate theincoming leading tape end to the speed of the outgoing tape end so thatboth tapes move at the same speed at the moment when the trailing tapeend and the leading tape end must be connected together while, at theend of the connection process, the newly incoming tape continues withoutjerks. This has the particular advantage that the connection of thetrailing tape end and the leading tape end is practically not stressedat all with tension so that the requirements placed on the strength ofthe connection can be kept low. As soon as the tape has been applied tothe strand of material to be taped, the leading tape end and thetrailing tape end are held firmly in any case because of the overlap.

As a further feature of the invention, it is provided that the tapefeeding device is equipped with a signal generator for the "tape end"signal in response to which the control device switches on therespective tape guiding drive for the full tape reel. An appropriatecontrol device then not only effects synchronism of the trailing tapeend and the leading tape end but simultaneously it also determines thetime and location at which the trailing tape end and the leading tapeend can be connected with one another.

As a further feature of the invention it is provided that the tapefeeding device is equipped, preferably in the region of the tape supplyarm, with a tacking device which connects the outgoing end of the onetape with the incoming end of the other tape. The term "tacking device"in the sense of the present invention relates to all devices with whichthe tape end and the tape leader can be connected with one another. Theconfiguration and mode of operation depend, for example, also on thetape material employed. For example, paper tapes can be connected withone another in a simple pressing process if the tape leader and the tapeend are given a coating of a so-called molecular adhesive. The tackingdevice, however, may also include a glue application device in additionto the pressing device. If tapes made of a thermoplastic material arebeing processed, the connection may be made by welding them togetherunder the influence of heat, radiation or also ultrasound. For metaltapes, the tacking device may be configured, for example, as a dotwelding device. However, this requires either a "flying" welding deviceor an additional tape drive must be provided for each tape reel to makeit possible to move by appropriate acceleration at least the outgoingtape end into a "reserve loop" so that the standstill period requiredfor a welding process is available at the welding location while,nevertheless, the tape feeding device continues to rotate and thepreviously formed "reserve loop" is reduced again. For metal tapes,particularly steel tapes, it is advisable, because of their much greaterstrength, to perform the joining of the trailing tape end and theleading tape end by way of a stamping-embossing process so that bothtapes are hooked into one another by way of a form-locking connectionand can be stressed with tension.

Another advisable feature of the invention provides that the tape supplyarm is tubular at least in the region where the tape makes first contactwith the strand of material. In this way, it is prevented that, at thehigh rate of rotation, the incoming tape is twisted due to windresistance or is caused to vibrate. Advisably, at least part of thetubular region is made of a transparent material.

As a further feature of the invention it is provided that a sensor forthe centrifugal force acting on the reel body is disposed in each tapereel. This sensor acts by way of a control device on the rotary drive ofthe tape feeding device and on the drive effecting the passage of thestrand of material so that the rate of rotation for the tape feedingdevice and the removal rate of the strand of material is varied as afunction of a predeterminable constant value for the centrifugal force.The ratio of the rate of rotation of the tape feeding device to theremoval rate for the strand of material is kept constant to correspondto the predetermined taping pitch. This arrangement makes it possible toinitially operate with a lower operating rate of rotation when the reelsare full and then to increase the rate of rotation of the tape feedingdevice as the coil diameter continues to decrease. The centrifugal forceacting on the respective reel body in operation is here a measure forthe decrease in coil diameter and constitutes the reference valueaccording to which the rate of rotation and the removal rate areregulated. Thus it is possible to operate the taping device always in anoptimum rate of rotation range. After a starting rate of rotationdetermined by the given centrifugal force, a progressive rise developsfor the remaining period of operation up to the maximum permitted rateof rotation which can be maintained until the end when the device mustbe braked again to lower rotation rates in order to enable the outgoingtape end to be connected with the incoming tape end. As a whole, it isthus possible to realize a considerable increase in production withimproved quality.

As another advantageous feature of the invention it is provided that asensor for the centrifugal force acting on the reel bodies is providedon each tape reel and acts by way of a control device on an adjustmentdrive for the mutually displaceable partial counterweights. Thisarrangement has the advantage that the taping device can be operatedpractically without imbalances since, on the one hand, the full supplyreel is fully balanced and is fixed to the tape feeding device by way ofits coupling. The tape reel in operation, which is also fixed with thetape feeding device by way of its coupling is likewise fully balancedsince with decreasing reel weight the two parts of the counterweight aredisplaced from one another about the circumference of the reel carrierso that, in this way, the reduction in weight of the tape reel iscompensated continuously.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in greater detail with reference toschematic representations of embodiments thereof, wherein:

FIG. 1 is a schematic longitudinal sectional view of a device forplacing tape around a cable;

FIG. 2 is a sectional view along line II--II of FIG. 1; and

FIG. 3 schematically illustrates a system for the regulation of ataping, system and includes a block circuit diagram.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The taping device shown schematically in FIG. 1 includes a tape feedingdevice 1 having a hollow housing 1a which is rotatably mounted in amachine frame 2 and is driven by way of a drive (not shown in detail) inthe direction of an arrow 3. A strand of material 4, for example acable, is guided coaxially with its axis of rotation through the housing1a of tape feeding device 1 in the direction of an arrow 5. The rate ofadvance of strand of material 4, on the one hand, and the rotationalvelocity of the tape feeding device, on the other hand, are matched withone another in such a way that a tape 6 coming in by way of tape feedingdevice 1 is wound around the strand of material at the pitch resultingfrom the ratio of the rate of advance of the strand of material to therate of rotation of the tape feeding device. The device is guided insuch a manner that the windings are made with overlaps. In addition tofabrics of natural and synthetic fiber material and/or wires, tapes madeof non-woven materials, plastic or metal foils including steel tapes arealso suitable as material for tape 6.

Tape feeding device 1 is connected with a tape supply arm 7 which isprovided with guiding devices 8, 9 in the form of guide fingers, rollersor the like. For automatic operation, the tape supply arm in theillustrated embodiment is additionally provided with a tacking device 10which makes it possible to firmly connect the trailing end of the tapecoming from a tape reel 11 with the incoming leading end of the tapefrom another tape reel 12 so that the taping process can continuewithout interruption. The type of the tacking device here depends on thematerial employed and if, for example, tapes of paper or plastic areemployed, may be a gluing device. For plastics, a configuration using awelding device is also possible, while for metal tapes a mechanicalconnection by means of a stamping-embossing device is advisable.

The two tape reels 11 and 12 are each arranged separately on a reelcarrier 13 and 14, with both reel carriers being mounted on the tapefeeding device so as to rotate independently of one another. Reelcarrier 13 as well as reel carrier 14 are provided with a counterweight15 on their sides facing away from tape reels 11 and 12, respectively.In the illustrated embodiment, this counterweight is divided into twopartial weights 15' and 15", with the two partial weights, in turn,being mounted on the reel carrier so as to be rotatable in mutuallyopposite directions relative to the axis of rotation. Each one of thetwo reel carries 13 and 14 has an associated controllable coupling 16and 17 which is configured, for example, as an electromagnetic couplingand by means of which the two reel carriers can be connectedindependently of one another with the rotating tape feeding device in amanner secure against rotation.

Moreover, reel carriers 13 and 14 are each provided with a brakingdevice, for example in the form of a brake disk 18 and 19, with which isassociated a corresponding brake caliper 20 and 21 at the machine frame2 so that, after release of coupling 16 or 17, reel carrier 13 or 14,respectively, can be fixed with respect to machine frame 2.

Reel carriers 13 and 14 are additionally each provided with a (guidingdevice 22) which may be provided, if required, with a drive (not shownhere) so that the leading end of the tape of each reel can be introducedinto the tape supply arm. Guiding device 22 of reel 12 has an associated(tape transfer member 23) which is fastened to the rotating tape feedingdevice and with which the respective beqinning of a tape can be advancedto the tape supply arm 7 in the region of tacking device 10.

In operation, reel carriers 13 and 14 are each provided with a full tapereel, with tape 6 from only one tape reel, for example tape reel 11,being applied to strand of material 4 by way of tape supply arm 7. Bothreel carriers are connected with tape feeding device 1 in a mannersecure against rotation by way of their couplings 16 and 17, with thealignment of guiding device 22 relative to tape supply arm 7 and tapetransfer member 23 being effected by means of positioning devices 24 and25, respectively. The function and operation of positioning devices 24and 25 will be described in greater detail below.

Each reel carrier is additionally connected with a respective signalgenerator, shown schematically at 13' and 14 which initiates a "tapeend" signal as soon as, for example, only a predetermined length remainson reel 11 presently in operation. This signal generator then switcheson a drive at guiding device 22 for tape reel 12 which introduces theleading end of its tape into tacking device 10 at the moment when thetrailing end of the tape from reel 11 passes through tacking device 10so that the tape end and the tape beginning can be connected with oneanother, thus applying an "endless tape" to strand of material 4.

In order for this changing process to take place reliably and withoutmalfunction, the above-mentioned signal generator reduces the rate ofrotation of the tape feeding device so that this process takes placewhile the entire system moves at a "creeping pace". As soon as thetacking process has taken place and the tape comes from reel 12, thesystem is switched back to its operational rate of rotation. During thisprocess, coupling 16 of reel carrier 13 carrying the empty tape reel 11is already being released and simultaneously brake 18, 20 is actuated sothat reel carrier 13 can be stopped at machine frame 2. By way of apositioning device 26 associated with the machine frame and incooperation between the controllable coupling and the brake, it isaccomplished that reel carrier 13 is stopped in a predetermined positionrelative to the machine frame. Now a reel lock of conventionalconfiguration and known in connection with cabling machines is releasedso that the empty tape reel 11 can be removed and replaced by a fulltape reel. This reel changing process advisably takes place by way of anautomatically controlled reel changing device.

As soon as reel carrier 13 has been provided with a full tape reel,brake 18, 20 is released and simultaneously coupling 16 is activated bymeans of a corresponding start-up control so that reel carrier 13 iscarried along by the tape feeding device which already rotates at theoperating rate of rotation and is accelerated to the operating rate ofrotation. The positioning device 24 associated with the rotating tapefeeding device now fixes reel carrier 13, by way of actuation of thecoupling, in its original position associated with tape supply arm 7 sothat again both reel carriers 13 and 14 rotate together with tapefeeding device 1 as a compact unit. As soon as the signal generator oftape reel 12 initiates the "tape end" signal, the above-described reelchanging process takes place in a corresponding manner for reel carrier14 which is likewise stopped in a precise position by a positioningdevice associated with the machine frame.

FIG. 2 is a sectional view of the structure and shows operation of thedivided counterweights 15' and 15". As can be seen in FIG. 1, eachpartial weight 15' and 15" is seated on its own guide ring on reelcarrier 13 so as to rotate coaxially with the passing strand of material4. The appropriate adjustment of the two partial weights relative to oneanother then compensates for the weight of tape reel 11 and 12,respectively, so that the two reel carriers each constitute a rotorwhich is balanced in itself.

Each one of tape reels 11 and 12 has its associated centrifugal forcesensor 28 which is connected with an (adjustment drive 29) for the twopartial weights 15' and 15". The two partial weights 15' and 15" alsohave an associated common centrifugal force sensor 30 which detects thecompensating centrifugal force of the partial weights resulting from thedisplacement angle of the two partial weights relative to one another.This sensor is also connected with the adjustment drive so that eachreel carrier is automatically balanced. If now tape is removedcontinuously from the tape reel, the centrifugal force acting on sensor28 goes down. The difference now resulting from the generatedcompensatory centrifugal force is equalized by way of adjustment drive29 in that it correspondingly increases the displacement angle betweenthe two partial weights 15' and 15". The design of the adjustment drivemust merely consider that tangential accelerations acting oncounterweights 15' and 15" are absorbed.

FIG. 3 shows, in the form of a block circuit diagram, a tape applyingsystem in which the strand of material 4 to be wound with tape isadditionally provided, after the application of the tape, with aprotective sheath of a thermoplastic material that is applied in acoextrusion process. The individual devices are indicated onlysymbolically, with the drives being shown separately to provide forbetter understanding of the control.

The system is essentially composed of a tape applying device representedby its tape feeding device 1, an extruder 31 which has an associatedcooling device 32 and a winding device 33. The strand of material 4 tobe taped and provided with a protective sheath is supplied by way of anunwinding station 34. Drive 35 for the taping device, drive 36 for theextruder, drive 37 for the winding device as well as drive 38 for theunwinding device are now linked with one another by way of a controlcircuit 39, with the linkage being predetermined by the desired pitchratio of the taping on the strand of material, that is, by the ratio ofthe rate of advance of the strand of material to the rate of rotation ofthe tape feeding device. This value is a fixed given value so that alldrives are adjusted to it. By way of the control of drive 36 forextruder 31, the control of extruder 31 is additionally actuated in theconventional manner. The centrifugal force sensor system of tapingdevice 1 is indicated by the dash-dot frame 40. This system provides thereference value for the control.

Since, as described above, each tape reel has an associated centrifugalforce sensor, it is possible with this linkage of all drives to realizean even further increase in performance of the system. With increasingreduction of the weight of the tape reel presently in operation, themass moment of inertia of the rotor composed of the tape feeding deviceand the two reel carriers is also reduced so that the rate of rotationof the tape feeding device can be increased in each case, thuspermitting operation of the tape applying device always in the optimumrate of rotation range. After a change of reels, that is, the connectionof an outgoing trailing tape end with the incoming leading tape end, thesystem is initially operated at a "creeping pace" at a starting rate ofrotation which is determined by a predetermined centrifugal force. Thenthere results for the remaining quantity on the reel a progressive risein the rate of rotation until the maximum permissible rate of rotationis reached which can be maintained until the respective signal generatorinitiates the "tape end" signal for the reel presently in operation andthe machine is returned to the "creeping pace". As a whole, it ispossible to realize a considerable increase in production in this way.

The arrangement of the tape reels and their radially oriented reel axesas shown in FIG. 1 is particularly advisable because this not onlyfacilitates the exchange of reels but also renders it possible to employtape reels which have a large diameter, while simultaneously keeping theradius of the reel carrier (which determines the mass moment of inertia)small. However, the axes of the tape reels may also be oriented parallelor at an angle to the axis of rotation on the tape feeding device. For amulti-layer tape application in only a single machine, two additionalreel carriers must then be provided in each case to correspond to thenumber of layers. If the axis of rotation is horizontal and the reeldisposed at the top is exchanged, the counterweight 15 now at the bottomthen has a stabilizing effect once the tape reel is released from thereel carrier.

What I claim is:
 1. A device for helically taping a continuous strand ofmaterial having a segment which extends along a straight path, thestraight segment of the strand having a longitudinal axis, comprising:amachine frame; a hollow housing through which the straight segment ofthe strand extends, the housing being mounted on the machine frame forrotation about the longitudinal axis of the straight segment; first reelmeans for holding a first tape having a beginning end; first reelcarrier means, on which the first reel means is mounted, for moving thefirst reel means along a path that encircles the longitudinal axis ofthe straight segment of the strand, the first reel carrier means beingrotatable with respect to the housing; first guiding device means forguiding the beginning end of the first tape; first releasable couplingmeans for selectively coupling the first reel carrier means to thehousing so that the first reel carrier means and the housing arerotatable in unison; first brake means for selectively fixing the firstreel carrier means with respect to the machine frame; second reel meansfor holding a second tape having a beginning end; second reel carriermeans, on which the second reel means is mounted, for moving the secondreel means along a path that encircles the longitudinal axis of thestraight segment of the strand, the second reel carrier means beingrotatable with respect to the housing; second guiding device means forguiding the beginning end of the second tape; second releasable couplingmeans for selectively coupling the second reel carrier means to thehousing so that the second reel carrier means and the housing arerotatable in unison. second brake means for selectively fixing thesecond reel carrier means with respect to the machine frame; and whereinthe first and second releasable coupling means and the first and secondbrake means are selectively operable during rotation of the housing topermit a depleted reel means to be replaced while the device continueshelically taping the strand.
 2. A device according to claim 1, whereinthe first coupling means comprises means for providing a controllablestart-up slip, and wherein the second coupling means comprises means forproviding a controllable start-up slip.
 3. A device according to claim1, wherein the first coupling means is configured as an electromagneticcoupling, and wherein the second coupling means is configured as anelectromagnetic coupling.
 4. A device according to claim 1, furthercomprising first position sensor means for sensing the position of thefirst reel carrier means relative to the machine frame, second positionsensor means for sensing the position of the second reel carrier meansrelative to the machine frame, and control device means, responsive tosignals from the first and second position sensor means, for selectivelyactuating the first and second brake means so as to effect, uponapplication of one of the brake means, a predetermined orientation ofthe respective reel means relative to the machine frame when therespective reel carrier means is at a standstill.
 5. A device accordingto claim 4, wherein the straight segment of the strand of material ishorizontally disposed and wherein, when one of the reel carrier means isstopped, the respective reel means is disposed above the straightsegment of the strand of material.
 6. A device according to claim 1,wherein the first reel carrier means is provided with at least onecounterweight for the first reel means, and the second reel carriermeans is provided with at least one counterweight for the second reelmeans.
 7. A device according to claim 6, wherein each counterweightrespectively comprises two partial weights which are mounted so as to beadjustable in the circumferential direction and in opposite directionsrelative to one another, and further comprising adjustment drive meansfor adjusting the two partial weights of each counterweight.
 8. A deviceaccording to claim 7, further comprising first centrifugal force sensormeans for the centrifugal force acting on the first reel means andsecond centrifugal force sensor means for sensing the centrifugal forceacting on the second reel means, and wherein the adjustment drive meansis responsive to signals from the first and second centrifugal forcesensor means.
 9. A device according to claim 1, further comprising tapesupply arm means, mounted on the housing, for directing tape toward thestrand of material, first positioning detector device means fordetecting the position of the first reel carrier means relative to thehousing, second positioning detector device means for detecting theposition of the second reel carrier means relative to the housing, andcontrol means, responsive to signals from the first and secondpositioning detector device means, for selectively actuating the firstand second releasable coupling means so that, in the operationalposition, both reel means are held in a predetermined orientationrelative to the tape supply arm means.
 10. A device according to claim9, wherein each reel carrier means is provided with a respective driventape guide which drives the respective tape at least while the beginningend of the respective tape is being threaded into the tape supply armmeans.
 11. A device according to claim 10, further comprising tape-endsignal generator means for generating a signal, when the tape held byone reel means is depleted, to actuate the driven tape guide for thereel carrier means on which the other reel means is mounted.
 12. Adevice according to claim 11, wherein the first and second tapesadditionally have terminating ends, and further comprising tackingdevice means for connecting the terminating end of one tape with thebeginning end of the other tape.
 13. A device according to claim 9,wherein the tape supply arm means has a tubular configuration at leastin the region where the tape starts to come in contact with the strandof material.
 14. A device according to claim 1, further comprising drivemeans for rotating the housing, additional drive means for moving thestrand of material along the path, and centrifugal force sensor meansfor sensing the centrifugal force acting on each reel means, and controlmeans, responsive to the centrifugal force sensor means, for controllingthe drive means and the additional drive means so that the rate ofrotation of the housing and the rate that the strand of material movesalong the path are varied as a function of a predetermined constantvalue for the centrifugal force, with the ratio of the rate of rotationof the housing to the rate that the strand material moves along the pathbeing kept constant corresponding to a predetermined helical tapingpitch.